1) Field of the Invention
The present invention relates generally to medical instrumentation and more specifically to a multi-lumen catheter with an integrated connector that facilitates the subcutaneous tunneling of the catheter after catheter tip placement, and simultaneous fluid communication with all of the multiple catheter lumens.
2) Description of the Prior Art
Catheters, generally, are hollow, flexible tubes for insertion into a body cavity, duct, or vessel to allow the passage of fluids or distend a passageway. Catheters are often used for temporary or long-term dialysis treatment. Dialysis treatment provides for blood to be withdrawn from the patient, purified, and then returned to the patient. Thus, in dialysis treatment, catheters are used to allow passage of a patient's blood into and out of the patient's body. For optimal performance during dialysis treatment, the catheter tips, both in-flow and out-flow, should be placed in close proximity to the heart. Typically, medical personnel use either a double lumen catheter or two single lumen catheters. Both types, however, present certain deficiencies.
While double lumen catheters (e.g., U.S. Pat. No. 4,895,561) allow for a single venous insertion of the catheter into the desired vein, double lumen catheters typically do not permit optimal catheter tip placement. Due to differences among patients, optimal tip position varies from patient to patient. Non-optimal tip position may significantly lower flow values, resulting in less effective dialysis treatment. For current double lumen catheters, a physician must make an estimate regarding the appropriate catheter tube length prior to beginning the procedure of catheterization. Then, a subcutaneous tunnel is made from the preferred end position of the hub assembly, namely, away from the neck of the patient in order to allow for more convenient access to the dialysis treatment equipment. The double lumen catheter tube is then tunneled forwardly and the tips of the catheter are inserted into the area to be catheterized. The estimated catheter tube length and subsequent forward tunneling may result in less than optimal tip placement.
With the use of two independent catheters (e.g., U.S. Pat. No. 5,776,111 to Tesio) the problem of tip placement is addressed. The hub assembly of each catheter is removable from the tube and tip portion of the catheter, thereby allowing the catheter tip to be placed directly into the vein and advanced into the desired position. Then, the proximal end of the catheter can be reversed tunneled and trimmed to a desired length. Thereafter, the hub assembly is attached. Deficiencies, however, exist in this method of catheterization as well. One problem associated with this method is that this method requires two separate venous insertions, namely, two tunnels and two of each accessory instrument used for the procedure. Therefore, there is increased surgical time required to place two catheters, there are two wound entry sites which doubles the risk of post-surgical infection, and the two catheters together are significantly larger in diameter than one double lumen catheter.
Applicant's co-pending applications Ser. No. 09/769,052, filed Jan. 24, 2001, and Ser. No. 10/086,033, filed Feb. 28, 2002, disclose a multi-lumen catheter apparatus and method for inserting the apparatus in a patient. The disclosures of these co-pending applications are hereby incorporated by reference. In the disclosed apparatus and method, a multi-lumen catheter includes a selectively attachable hub assembly that allows the catheter tip to be positioned accurately within a patient's vein prior to subcutaneous tunneling. The distal end of the catheter tube is selectively attachable to the hub assembly. Accordingly, after the tips of the catheter have been accurately positioned in a patient, the other end of the catheter may be reverse tunneled under the skin of a patient. Specifically, after tip placement, an incision is made in the skin adjacent to the point where the protruding distal end of the catheter exits the skin. A subcutaneous tunnel is then formed having a first end at the incision and a second end exiting the skin at a point remote from the first end of the tunnel. The distal end of the catheter tube is passed through the subcutaneous tunnel and a tissue stabilizing cuff is seated therein, thereby stabilizing the tunneled portion of the catheter tube in the patient. A selectively attachable hub assembly is connected to the lumens at the distal tip of the catheter tube for subsequent connection of the catheter to a dialysis machine.
During the above procedure, guiding the distal end of the catheter tube through the subcutaneous tunnel can be problematic. It is known to engage the end of the catheter tube to a trocar extending through a subcutaneous tunnel for guiding the catheter tube through the tunnel with the trocar. Typically, however, a tip of the trocar includes barbs, ridges, threads, or the like for insertion into one of the lumens at the distal end of the catheter tube, thereby forming a friction or interference fit between the interior surface of the catheter and the barbs or ridges on the tip of the trocar. Unfortunately, the frictional engagement between the trocar tip and the catheter tube may be insufficient to withstand forces exerted on the catheter tube as the tube and adjoined trocar are passed through the tunnel, thereby causing the catheter tube to loosen and separate from the trocar. Also, because such a trocar engages only one lumen of a multi-lumen catheter, the shaft of the trocar and the catheter tube are not concentrically aligned, thereby forming a discontinuity which can impede passage of the trocar and adjoined catheter tube through the tunnel, and thereby increasing the likelihood of separation between the trocar and catheter tube.
The inventors are aware of a tunneling device that includes a trocar with a threaded tip for engagement in a connector that is releasably attached to the distal end of a multi-lumen catheter tube. One problems with this device included is that the connector is difficult to manipulate because of its small size. Also, use of this tunneling device necessarily required multiple steps, including: a) connecting one end of the connector to the end of the catheter tube; and b) connecting the other end of the connector to the tip of the trocar so that the catheter can be routed through a subcutaneous tunnel with the trocar. Though this tunneling device has proven to be adequately secure in most instances, the nature of the releasable attachment does not completely eliminate the possibility that the connector may disengage from the catheter tube as the connector and tube are guided through a subcutaneous tunnel via the trocar.
Therefore, there is a need for an improved connection between the trocar and the distal end of a multi-lumen catheter tube which provides more positive and aligned engagement between a trocar and the distal end of a multi-lumen catheter tube for guiding the catheter tube through a subcutaneous tunnel with a minimal number of separate component parts and process steps.
Another shortcoming of known apparatus and methods for catheterization of patients with multi-lumen catheters is the need to individually flush each of the multiple lumens of the catheter with a flushing solution to clear the lumens of debris, tissue, or the like prior to connection of the catheter to a dialysis machine. Flushing the lumens in a sequential manner adds time to the catheter insertion procedure. Known multi-lumen catheter systems described above also require sequential flushing of each of the multiple catheter lumens. Therefore, there is a need for an apparatus and method which permit simultaneous flushing of multiple catheter lumens in a multi-lumen catheter system.